Accidental discharge is the event of a firearm firing (discharging) at a time not intended by the user. Perhaps most commonly, accidental discharges (sometimes called ADs by military and police personnel and sometimes referred to as negligent discharges) occur when the trigger of the firearm is deliberately pulled for a purpose other than shooting (such as demonstration, function testing, or dry-fire practice, for example) while ammunition is present in the chamber. Another, second common cause of accidental discharges occurs when the gun-handler places his finger on the trigger before he has decided to shoot. With the finger being so positioned, many events may cause the finger to compress the trigger unintentionally. For example, if one attempts to holster the firearm with his finger on trigger, the holster edge will drive the finger onto the trigger, causing a likely discharge. If one stumbles or struggles (with an adversary) with his finger on the trigger, the grasping motion of both hands will likely cause the trigger finger to press the trigger.
On occasion, an accidental discharge can occur for a reason other than the finger pulling the trigger, such as dropping a loaded weapon (whether or not secured around the torso of the user with a sling). Because of this possibility, most of the recently produced pistols are designed with a “drop-safety” or firing pin block, a mechanism inhibiting or isolating the firing pin, preventing accidental discharge if the firearm is dropped. However, most long guns do not have drop-safety features. Another common incidence of accidental discharge of the firearm (in particular, assault rifles) occurs when the user lets the rifle go and, before the rifle hangs on a sling over the user's torso, the rifle rubs against the torso and the items of user's clothing on its way to the hanging position. Any item protruding from the clothing of the user can and often does depress the trigger upon interaction with the dropped firearm. While gun safety rules recognize these possibilities and aim to prevent them, it is the tangible safety features—such as, for example, a trigger lock (an example 110 of which is shown in FIG. 1A, depicting a firearm 112) and a mechanism often called a “safety” (such as an external safety lever or latch on the side of the firearm or a grip safety mechanism of a handgun, an example 120 of which is shown in FIG. 1B, depicting a portion 122 of a firearm)—that are relied on to prevent an accidental discharge.
However, in the heat of the moment or just because of the mundane inattention, the user often simply forgets to activate the firearm's external, manual safety such as the safety 120 (interchangeably referred to herein as an external safety latch, manual safety latch, primary safety, or a primary safety mechanism), thereby negating the very purpose of the primary safety.
As far as a trigger lock mechanism is concerned, generally, two pieces come together from either side behind the trigger and are locked in place to form a lock that is substantially immovable and not repositionable unless unlocked with a key or combination. This physically prevents the trigger from being pulled to discharge the weapon. Other types of trigger locks do not go behind the trigger, but encompass the full area behind the trigger guard making the trigger inaccessible. It is well recognized in the art, however, that trigger locks are not designed to be used on loaded guns (see, for example, discussion in “Hype Over Trigger Locks Provokes Fear of Firearm Accidents”, E. Slater, Los Angeles Times, Feb. 16, 1999), which makes them basically useless for preventing negligent discharges. It is also well understood that the existing safety measures, while effective in majority of situations, occasionally may fall short of being “fool-proof” and providing a peace of mind to a responsible armed citizen.
There remains an unmet need, therefore, for a firearm safety feature that compensates for the discharge accidents that are not prevented by the primary safety mechanism